Modification of grain boundary potential barriers by annealing treatments of PTCR ceramics with identical microstructure and room-temperature resistivity. Issue 16 (December 2021)

• Record Type: Journal Article
• Authors: Prohinig, Jennifer M.; Reichmann, Klaus; Bigl, Stephan
• Is Part Of: Journal of the European Ceramic Society. Volume 41:Issue 16(2021)
• Page Start: 179
• Page End: 187
• Publication Date: 2021-12
• Subjects: Grain boundary -- Potential barrier -- Defects -- Temperature treatment -- Varistor effect; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2021.08.014
• Languages: English
• ISSNs: 0955-2219

Abstract

Graphical abstract: Abstract: Semiconducting BaTiO3 -based ceramics originating from the same starting powder batch were subjected to different oxidative post-sintering treatments at temperatures between 800 °C and 1200 °C. The annealing profiles were chosen in a way to result in ceramics with same room-temperature and microstructure. However, the different annealing procedures clearly affected the resulting PTCR characteristics above and below the phase transition temperature. Observed changes in electrical properties were investigated by capacitance-voltage measurements and x-ray diffraction. It was found that annealing treatments influence the grain boundary potential barrier height and width by modifying the equilibrium concentration of cation and oxygen vacancies. Moreover, oxidative annealing at 1100 °C appears to influence the temperature development of spontaneous polarization by filling up oxygen vacancies within the grain bulk. These findings not only extent existing knowledge about defect equilibria in barium titanate but also emphasize the strong impact of process parameters on electrical properties of electroceramics.